Abstract

Metal Injection Moulding (MIM) is a promising new production technology for small to medium sized parts with high geometric complexity as they are found in turbomachinery like aero engines or turbochargers. This study concerns the feasibility of manufacturing parts from nickel-based superalloy CM247LC via MIM and in particular the determination of optimum sintering and thermal processing parameters. CM247LC poses a serious challenge for MIM processing. Because of its high aluminum content, the strength potential is very high, but the sintering capability is severely restricted. Differential scanning calorimetry (DSC) and dilatometry measurements as well as ThermoCalc simulations are used to optimize the sintering step of the MIM process route. Carbon, nitrogen and oxygen contents of the powder and the as sintered specimens are measured to evaluate the pick up of impurities during processing. The microstructure of the as sintered specimens is characterized with respect to residual porosity, grain size and γ' precipitation size and morphology. Room temperature strength and elongation in the MIM material are found to surpass conventional HIP material which is attributed to the very fine grain size. Density and mechanical properties are observed to drop at the highest sintering temperatures. Ways to further improve the microstructure and strength will be discussed, in particular for high temperature applications.